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Epidemiology

The incidence of the disease is estimated to be 1 in 3600 in Ashkenazi Jews with a carrier frequency of 1 in 30 and 1 in 360,000 in other population with a carrier frequency of 1 in 300. Tay-Sachs disease is the most frequently occurring sphingolipidoses.

Pathology

Tay-Sachs is due to a mutation of the HEXA gene that results in reduced levels of the enzyme hexosaminidase-A (hex-A) which in turn results in the accumulation of GM2-ganglioside within the cells of the nervous system 3-7.

10 months and older

As a child with Tay-Sachs grows older, he or she may become blind, intellectual impaired, paralyzed, and unresponsive to the environment. The child also may have seizures, difficulty swallowing, and difficulty breathing. Children with Tay-Sachs disease rarely live beyond 4 or 5 years of age 1-7.

Screening

Screening for Tay-Sachs disease is recommended for people in high-risk groups. This includes people of Ashkenazi Jewish descent and anyone with a history of the condition in their family.

preconception screening: where potential parents are able to check whether they carry the HEXA mutation before starting a family

antenatal screening: where a fetus is checked to see whether two copies of the HEXA mutation have been inherited, which would cause Tay-Sachs disease to develop

Radiographic features

CT

Macrocephaly and reduced attenuation of the cerebral white matter have been reported on CT scans in patients with GM2 gangliosidosis 5.

MRI

MRI is superior to CT in delineating deep white matter demyelination. Thalami may show changes consistent with calcification, best seen on T2* weighted sequences. No abnormal contrast enhancement is described 1-5.

Treatment and prognosis

No specific treatment is currently available for Tay-Sachs disease. Management is therefore supportive.